1. Technical Field
Agents and compositions thereof are described herein that are E-selectin antagonists and may be used as therapeutics. Methods and uses for these E-selectin antagonists for treating and preventing diseases, disorders, and conditions associated with E-selectin activity are described herein.
2. Description of the Related Art
Many pathological conditions such as autoimmune and inflammatory diseases, shock, and reperfusion injuries involve abnormal adhesion of white blood cells. When abnormal adhesion of selectin-mediated cell adhesion occurs tissue damage may result instead of repair. Selectins include three cell adhesion molecules that have well-characterized roles in leukocyte homing. E-selectin (endothelial selectin) and P-selectin (platelet selectin) are expressed by endothelial cells at sites of inflammation or injury. Recent investigations have suggested that cancer cells are immunostimulatory and interact with selectins to extravasate and metastasize (see, e.g., Gout et al., Clin. Exp. Metastasis 25:335-344 (2008); Kannagi et al., Cancer Sci. 95:377-84 (2004); Witz, Immunol. Lett. 104:89-93 (2006); Brodt et al., Int. J. Cancer 71:612-19 (1997)).
A number of cancers are highly treatable when treated before the cancer has moved beyond the primary site. However, often once the cancer has spread beyond the primary site, the treatment options are limited and the survival statistics decline dramatically. For example, when colorectal cancer is detected at a local stage (i.e., confined to the colon or rectum), over 90% of those diagnosed survive more than five years. Conversely, when colorectal cancer has spread to distant sites (i.e., metastasized from the primary site to distant sites), the five-year survival rate of those diagnosed drops dramatically to only 11%.
The most common types of cancer include prostate, breast, lung, colorectal, melanoma, bladder, non-Hodgkin lymphoma, kidney, thyroid, leukemias, endometrial, and pancreatic cancers based on estimated incidence for 2012. The cancer with the highest expected incidence is prostate cancer, with more than 240,000 new cases expected in the U.S. in 2012, and the lowest expected incidence is pancreatic cancer, with approximately 44,000 new cases expected in 2012.
The highest mortality rate is for patients who have lung cancer. More than 160,000 patients are expected to succumb to the disease in 2012. Despite enormous investments of financial and human resources, cancer such as colorectal cancer remains one of the major causes of death. Colorectal cancer is the second leading cause of cancer-related deaths in the United States of cancers that affect both men and women. Over the last several years, more than 50,000 patients with colorectal cancer have died every year.
The four hematological cancers that are most common are acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), and acute myelogenous leukemia (AML). Leukemias and other cancers of the blood, bone marrow, and lymphatic system, affect 10 times more adults than children; however, leukemia is the most common childhood cancer, and 75% of childhood leukemias are ALL. AML is the most common leukemia in adults. Approximately 47,000 new cases are diagnosed every year, and approximately 23,500 people die every year from leukemia.
Cancer therapeutic drugs may contribute to endothelial injury, which can in turn cause venous thromboembolism (VTE). Other risk factors that predispose an individual to VTE include stasis or endothelial injury (e.g., resulting from indwelling venous device; major trauma or injury), medical conditions, (e.g., malignancy, pregnancy, cardiovascular conditions or events), administration of other drugs such as hormones, and thrombophilia. Blockage of the flow of blood in a body deprives tissue of oxygen and results in damage, destruction or death of the tissue. A thrombus and an embolism can lodge in a blood vessel and block the flow of blood. In the United States, approximately 900,000 cases of VTE, which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), are diagnosed annually and about 300,000 cases are fatal (Heit et al., Blood 2005; 106 (abstract)). Venous thrombosis occurs when red blood cells and fibrin, and to a minor degree, platelets and leukocytes, form a mass within an intact vein. Typically, a pulmonary embolism occurs when a thrombus or a portion of the thrombus detaches from a vein wall and lodges within a pulmonary artery. Because signs and symptoms of VTE are nonspecific and difficult to diagnose, the exact incidence of VTE is unknown but may have an annual incidence of 0.1-0.2% (see, e.g., Anderson et al., Arch. Intern. Med 151:933-38 (1991); Silverstein et al., Arch. Intern. Med. 158:585-93 (1998)).